Preventing Pompeii

When the earth rumbles, slides, or erupts, 'who you gonna call'? Earth scientists reduce risk.

The need to curb manmade climate change has the world's attention. But what of the natural environmental dangers that humans do not cause and cannot control?

Earth scientists such as volcanologist Jonathan Fink say these too should be front and center in environmental planning. Humans can't curb volcanic eruptions, earthquake shaking, or natural climate change. But they can reduce the risk to themselves through land-use planning, building codes, and community preparedness. The underlying question, Dr. Fink says, is how to maintain public attention to this when destructive events happen only once in two decades or so.

A geologist at Arizona State University in Tempe, Fink joined fellow scientists to highlight this concern during a meeting of the American Geophysical Union last month in San Francisco. They said they are encouraged by progress in scientific understanding of natural dangers. But they lamented the general lack of national and local public commitment to sustaining that research and putting the knowledge to practical use in community planning.

For example, the volcanologists think the next 10 years can bring a major improvement to volcano forecasting. Right now, Fink said, volcanologists can't satisfactorily predict large eruptions with major fatalities or ash eruptions that can clog jet aircraft engines. He listed what he called the "big questions" in volcano forecasting: Is magma rising beneath a volcano? How much? How fast? What type? Will it explode? When will unrest end? These questions are hard to answer even at intensely monitored hot spots such as Mexico's Popocatepetl or Italy's Vesuvius. Yet, Fink expects that "in the next 10 years ... we may approach big answers" to these "big questions."

Stanford University geophysicist Paul Segall agrees that "there's a confluence of a lot of things going on that should improve our ability to make predictions in the next 10 years." He notes that satellites can pick up millimeter-size changes in a volcano's surface that indicate magma build up. Other scientists described how portable seismic instruments can radio data with which computers create three-dimensional images of a volcano's chambers. The global-positioning-satellite navigation system can detect bulging ground. Gas "sniffers" can monitor telltale chemical changes in volcano breath.

Prevention is doable

Put all this together over the next decade, and "unlike earthquake prediction, we can actually do something about volcanoes," Dr. Segall says. Fink adds that, while forecasters had only 3 months warning of the Mt. St. Helens eruption, he hopes for 6 months to a year of eruption warning by 2010.

But there's a caveat.

Fink noted that, in the United States, the know-how to put scientific knowledge to practical use is embodied largely in US Geological Survey (USGS) experts. Many of these are due to retire over the next decade with no replacements in sight. Asked about this again last week, Fink said he thinks "this is a real issue." He explained that "we need to get young people into the program ... to gain experience working with the older people." Otherwise valuable expertise will be lost.

Yet young seismologists see better career prospects in academia or industry. As memory of Mt. St. Helens fades, Fink considers the lack of national commitment to a strong volcanology program that can attract talent to be one of the biggest volcano risks the US now faces.

Waverly Person, chief of the USGS National Earthquake Information Center in Golden, Colo., also sees lack of public commitment as a significant environmental risk. He explained in a telephone interview that this has not shown up as a shortage of replacement personnel in USGS seismology "at this time." However, it is often reflected in public reluctance to embody seismic scientific knowledge in strict building codes and local zoning.

Unlike volcanologists, seismologists don't expect to be able to predict specific quakes in specific areas in the foreseeable future. They can, however, map earthquake hazards region by region and town by town.

Earthquake destruction "is a risk we can control," Dr. Person says.

But, he adds, "It's slow to get people into it" unless they're constantly reminded of the danger. Quake-resistant building is expensive. In California, they're true believers and willing to pay the price. It's a different story in the New Madrid Seismic Zone along the Mississippi River through Arkansas, Missouri, and Tennessee.

That region hasn't been badly shaken since the 1811-12 quakes reversed the course of the Mississippi and rang church bells more than 750 miles away in Boston. Nearly two centuries of seismic peace have bred complacency in what seismologists consider a high-risk zone. The exact degree of risk is unknown.

No catastrophic quake

There is good geological evidence that several strong quakes have occurred in the New Madrid zone over the past 2,000 years. Peggy Cuccione at the University of Arkansas and several colleagues studied slippage along a portion of the zone a few years ago. They concluded that the risk of a major event may be higher than has been thought.

Yet Joseph Engeln at the University of Missouri-Columbia and colleagues reached a different conclusion after studying current movement along the New Madrid fault using the global positioning system. They consider a very large, magnitude 8.0, quake unlikely for several thousand years. That's cold comfort. They also see the possibility that a smaller magnitude 6.0 quake - large enough to cause substantial damage - could occur in the near future.

Dr. Person says the bottom line is that, given the development of the region over the past two centuries, even a moderate quake could be a disaster to an unprepared community in the New Madrid region. He explains that seismologists will persist in getting out the word. It's up to the local communities to translate that into effective and, admittedly, more-expensive building codes.

Meanwhile, tsunamis, often misnamed tidal waves, are challenging a different kind of complacency. Bathers along southern California who haven't given a thought to these giant waves should think again. Scientists had thought tsunamis occur rarely and are generally triggered remotely. Nations rely on an efficient Pacific-wide alert system to give timely warnings. Costas Synolakis from the University of Southern California at Los Angeles told the geophysics meeting that scientists have changed their minds. He said they now believe that "tsunamis are more common than we had thought and they can strike with only a few minutes' warning."

Several research teams reported that many giant waves are caused locally by offshore underwater landslides. Earthquakes can trigger the the slides. Ground water oozing through underwater sediment banks can also cause slumping. Garry Greene from the Monterey Bay Aquarium Research Institute showed maps of at least two slope failures in the central Santa Barbara channel.

Mandatory: manage risk

This is a new risk to be managed. A wall of water up to 50 feet high sweeping over a highly developed coastline could be devastating. Scientists reporting the danger said that local warning systems could be established that would give bathers and beach house residents the few minutes they would need to escape to higher ground. Zoning codes can be reviewed to preclude building in areas tsunamis might reach.

As with other natural hazards over which humans have no control, geophysicists consider this latest addition to the list as another opportunity to turn alertness to danger into action to reduce avoidable risk.

(c) Copyright 2001. The Christian Science Publishing Society

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